1. Field
This disclosure relates generally to Schmitt Triggers, and more specifically, to a Schmitt trigger having a test circuit and method for testing the Schmitt trigger.
2. Related Art
Schmitt trigger circuits are used in a variety of applications. A Schmitt trigger functions like a comparator with hysteresis, where the output voltage of the Schmitt trigger switches at a different input voltage depending on whether the input voltage is ramping up or ramping down. A conventional method for testing a Schmitt trigger is to simply ramp up and ramp down the input voltage while monitoring the output voltage changes. The input voltage that results in the output voltage changing when the input voltage is ramping up is the high hysteresis threshold voltage. The low hysteresis threshold voltage is determined by ramping down the input voltage until the output voltage changes. A drawback in this test method is that it requires a significant amount of time to ramp the input voltage while monitoring the output.
Therefore, what is needed is a Schmitt trigger, test circuit, and method for testing that determines the hysteresis threshold voltages more quickly.